Golang中HTTP服务的分析与设计详解

type Server struct { // 请求监听地址 Addr string // 请求核心处理函数 Handler Handler }

http.ListenAndServe(httpAddr, nil) // ListenAndServe always returns a non-nil error. // 创造了一个server对象并调用ListenAndServe func ListenAndServe(addr string, handler Handler) error { server := &Server{Addr: addr, Handler: handler} return server.ListenAndServe() } func (srv *Server) ListenAndServe() error { // 如果关闭了http监听则直接返回ErrServerClosed if srv.shuttingDown() { return ErrServerClosed } addr := srv.Addr if addr == "" { addr = ":http" } // 开启net包的Listen监听方法，根据传入的类型返回监听的对象 ln, err := net.Listen("tcp", addr) if err != nil { return err } return srv.Serve(ln) }

func (srv *Server) Serve(l net.Listener) error { if fn := testHookServerServe; fn != nil { fn(srv, l) // call hook with unwrapped listener } origListener := l l = &onceCloseListener{Listener: l} defer l.Close() if err := srv.setupHTTP2_Serve(); err != nil { return err } if !srv.trackListener(&l, true) { return ErrServerClosed } defer srv.trackListener(&l, false) baseCtx := context.Background() if srv.BaseContext != nil { baseCtx = srv.BaseContext(origListener) if baseCtx == nil { panic("BaseContext returned a nil context") } } var tempDelay time.Duration // how long to sleep on accept failure // 将整个Server对象设置进ctx中，在多个goroutinue中共享 ctx := context.WithValue(baseCtx, ServerContextKey, srv) for { rw, err := l.Accept()   // 阻塞等待连接 if err != nil { select { case <-srv.getDoneChan(): return ErrServerClosed default: } if ne, ok := err.(net.Error); ok && ne.Temporary() { if tempDelay == 0 { tempDelay = 5 * time.Millisecond } else { tempDelay *= 2 } if max := 1 * time.Second; tempDelay > max { tempDelay = max } srv.logf("http: Accept error: %v; retrying in %v", err, tempDelay) time.Sleep(tempDelay) continue } return err } connCtx := ctx if cc := srv.ConnContext; cc != nil { connCtx = cc(connCtx, rw) if connCtx == nil { panic("ConnContext returned nil") } } tempDelay = 0 c := srv.newConn(rw) c.setState(c.rwc, StateNew, runHooks) // before Serve can return go c.serve(connCtx)  //Serve a new connection 建立新的连接 } }

// serverHandler 代表请求对应的处理逻辑 type serverHandler struct { srv *Server } // 具体的处理函数 func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) { handler := sh.srv.Handler //如果入口设置传入了`Handler`，那么调用的就是传入的，否则就是DefaultServeMux if handler == nil { handler = DefaultServeMux } if req.RequestURI == "*" && req.Method == "OPTIONS" { handler = globalOptionsHandler{} } if req.URL != nil && strings.Contains(req.URL.RawQuery, ";") { var allowQuerySemicolonsInUse int32 req = req.WithContext(context.WithValue(req.Context(), silenceSemWarnContextKey, func() { atomic.StoreInt32(&allowQuerySemicolonsInUse, 1) })) defer func() { if atomic.LoadInt32(&allowQuerySemicolonsInUse) == 0 { sh.srv.logf("http: URL query contains semicolon, which is no longer a supported separator; parts of the query may be stripped when parsed; see golang.org/issue/25192") } }() } handler.ServeHTTP(rw, req) }

package framework import "net/http" type Core struct { } func (c Core) ServeHTTP(writer http.ResponseWriter, request *http.Request) { panic("implement me") } func NewCore() *Core { return &Core{} }

package main import ( "log" "net/http" "testdemo1/coredemo/framework" ) func main() { server:=&http.Server{Addr: ":8080",Handler: framework.NewCore()} err := server.ListenAndServe() if err!=nil{ log.Fatal(err) } }